Patent attributes
Misfire of an engine is detected by extracting a pressure component of combustion from an output of a pressure sensor disposed in a cylinder. An engine misfire detection apparatus obtains a combustion parameter Cr that is a correlation between a reference signal Fc synchronous with the combustion cycle of the engine and cylinder pressure Pc obtained from an output of a pressure sensor disposed in the cylinder. The apparatus detects a misfire of the engine based on the combustion parameter. A misfire can be accurately detected even under a low load condition because the combustion parameter indicating the combustion component is extracted from the cylinder pressure as a correlation between the reference signal synchronous with the combustion cycle of the engine and the cylinder pressure obtained from the sensor output.
